A331589 a(n) is the greatest k such that A331587(n) = k * reverse(k) (where reverse(k) is the binary reversal of k, A030101(k)).

1, 3, 5, 7, 9, 13, 15, 17, 21, 25, 29, 27, 31, 33, 41, 49, 45, 57, 53, 51, 61, 59, 63, 65, 73, 81, 97, 89, 85, 105, 113, 101, 93, 121, 99, 109, 117, 107, 115, 125, 123, 119, 127, 129, 145, 161, 153, 177, 169, 193, 165, 185, 209, 201, 225, 181, 197, 217, 241

Offset: 1

Author

Rémy Sigrist, Jan 21 2020

Keywords

• nonn
• base

Links

• Rémy Sigrist, Table of n, a(n) for n = 1..8347
• Rémy Sigrist, PARI program for A331589

Crossrefs

Cf. A030101, A331587, A331588.

Programs

PARI

See Links section.

Formula

a(n) = A030101(A331588(n)).

a(n) * A331588(n) = A331587(n).